Chapter 3: Range is Not an Issue

Range Is a Matter of Engineering

One of the major misperceptions regarding 802.11b and other wireless protocols is that the range is limited to 100 meters and thus proves impractical as a last-mile solution. The truth is that with proper engineering, 802.11b can reach beyond 20 miles point to point. In the quest for Public Switched Telephone Network (PSTN) bypass, this is one of the most exciting revelations. By steering an antenna in the direction of the subscriber's home, the service provider can bring broadband wireless to masses of homes without stringing a single strand of copper wire, digging up a single street, or engaging in a single legal battle for right-of-way.

Furthermore, new wireless protocols for metro area networks (MANs) provide for the construction of wireless networks that can cover entire cities. Ad hoc peer-to-peer networks stretch the range of a wireless network with a minimum of investment.

This chapter covers the science of antennas and how proper engineering can stretch the most modest resources to deliver essential services to the home. Secondly, this chapter explains how 802.11b antenna systems can be used to stretch the range of delivery out to a number of miles to blanket large metropolitan areas and even reach out to rural subscribers. The most important part in designing a broadband wireless network is the inclusion of the new protocol 802.16 in the deployment of wireless metro area networks (WMANs) to feed suburban 802.11b networks. Other technologies such as mesh networks also extend the range of broadband wireless networks.

In data networking, the success of 802.11 has inexorably linked it with radio frequency (RF) engineering. Whereas a wired network requires little or no knowledge on the part of the installer of how data travels via an Ethernet cable, a wireless network requires a strong knowledge of radios and antennas. The following paragraphs provide a basic overview of wireless transmission systems.